1. Field of the Invention
The present invention relates to a liquid silicone rubber coating agent composition that is particularly useful for the fabric for an air bag such as a curtain air bag that contains a silicone rubber coating film formed on a fibrous fabric such as 6,6-nylon, and also relates to a curtain air bag that uses such a composition.
2. Description of the Prior Art
Conventionally, the types of air bag silicone rubber compositions described below have been proposed for forming a rubber coating on a fibrous surface. Specifically, a liquid silicone rubber composition for an air bag with excellent adhesion to base fabrics, prepared by adding an inorganic filler, a siloxane resin, and an epoxy group-containing silicon compound to an addition curable composition (patent reference 1); a liquid silicone rubber coating agent composition that develops excellent adhesion to base fabrics upon heating for a short period at a low temperature, prepared by adding an inorganic filler, a siloxane resin, an organotitanium compound, and an alkyl silicate to an addition curable composition (patent reference 2); a silicone rubber composition for an air bag with excellent thin-film coating characteristics, in which the viscosity of a vinyl group-containing organopolysiloxane is restricted (patent reference 3); and a coating composition for a rubber-coated fabric with reduced tackiness, prepared by adding a wet silica with an average BET specific surface area within a range from 150 to 250 m2/g and an average particle size of no more than 20 μm to a rubber coating composition (patent reference 4) have been proposed.
However, when these compositions are used in the preparation of a curtain air bag, which unlike the air bags installed for the driver's seat and passenger seat, are provided along the edge of the roof from the front pillar, and must be capable of maintaining an inflated state for a certain period of time in order to protect the region around the head and prevent people being flung from the car during a collision or rollover of the vehicle, none of the compositions is able to satisfactorily suppress leakage of the inflator gas, enabling the inflation time to be sustained for a satisfactory period.
[Patent Reference 1] U.S. Pat. No 5,877,256
[Patent Reference 2] JP 2002-138249A
[Patent Reference 3] JP 2001-287610A
[Patent Reference 4] U.S. Pat. No. 6,387,520